Ultimate Bass Pedal

[bluelang]

Hello,

First post.. I've built several thingums in the past, including a from-scratch tube amp, but now I'm playing bass in a band and want the ultimate bass pedal. I've sketched out a diagram, but it's already at 3 switches and 6 knobs, so I thought I'd post it and get some feedback.

In the middle section, I'm thinkin' I want to split it and be able to boost the bass independently of the fuzz. I'd probably put an internal pot to set the blend permanently.

Then there's a mixer pot to mix back the compressed section with the fuzz/bass boosted section for that fat LA sound.

Drive 1 and Drive 2 would be FET for some even order harmoniosity. Maybe overkill / stupid? I'm assuming an 18 volt single supply to get enough headroom and also assuming the input buffer might have to cut the signal back to give enough headroom for all the bs internally?

Disaster? Genius? Retarded?

[nosamiam]

Get out your breadboard and go for it! Sounds like a cool project. I see some TL074s in your future!

Oh, and a big enclosure for knobs + 2 batteries.

[Quackzed]

that looks really good...
just about everything i usually do when recording bass.
here are some ideas
-you may not need the first buffer if the (drive 1 ) has a high input imedence and is always on... it will do double duty
-you could use a splitter/blender type circuit for the splitting and mixing section and be able to use different fuzzes/effects
    you could split the signal into three parts..
          one signal goes through the eq circuit  to mixer section
          one signal goes through the compressor circuit to mixer section
          and last signal goes to an send jack (to your pedal of choice)to a return jack , to mixer
-and you may not need the last buffer if the drive2 circuit has low output impedence/ or ,if you switch the drive2 in/out, as long as the mixer also has low output impedence, the signal may not need the buffer...

[petemoore]

  18v for such an endeavor.
  Buffer won't hurt.
  Drive...which one though, you've probably picked one out.
  I'd like to take a look at the 'Split' circuit, otherwise the block diagram goes to another...does split mean full bandwidth doubling of signal paths or will there be some frequency splitting or otherwise Eq'ing the splits ?
  Split [*bassEQ/*fuzz   // compressor.
  Is the compressor going to be a ~full range bandwidth? 
  Here's the take unboiled:
  Low bass distortion/fuzz...can be buzzy and the speakers might care etc.
  Compression Otoh, on the lowerest frequencies can make it easier to bring up the thunder-rumble...evenly...up to...but not past what the cabinet/speakers can handle.
  Fuzzing the upper ranges is more similar to guitar...
  enough rambling, it looks like the thought experiments and something I'd type about or even thinking of building something [just got bass really humpin' on the recordings etc.] with similar block diagram, not sure if you're including frequency splitting though.
  And I'm soon going to post about sub-bass, bass, mids, and how to get a LF signal to feed...well that's where I'm at...I have an EV-15, but would like smaller driver in a twisted tube...OT ramblin' again.
  Happens this way when rambling about a multi-tiered block diagram that requires scrolling, there are at least enough options to ramble on about until time folds.
  Anyway the basic signal flow paths have what looks like the right stuff for a big bass rig [you may have to pick 'n choose your distorter, twiddle the comp etc.].
 

[DerHoggz]

I personally prefer modularity (is that a word?), and as such, feel that this does not pass Occam's razor.  Maybe break it down further?

However, it is you're decision.

[bluelang]

I personally prefer modularity (is that a word?), and as such, feel that this does not pass Occam's razor.  Maybe break it down further?

However, it is you're decision.

I know what you're sayin', but I specifically want those aspects in parallel... and I don't want to lug 3 pedals and an fx loop.

[aziltz]

effects loop!   right ther in the middle!

[bluelang]

Got a start on the breadboard today.. Gonna use some NTE quads to get it rolling and then maybe switch to an AD for the real build.

I've simplified it a bit based on the advice above:



Thanks a bunch to everyone for replying.

Pete, I was thinking that fuzz tends to clip the signal, which will attenuate the lows. That's why there's a second parallel line to boost the bass. I figure mixing that all together with the compressed signal - which right now I guess will be full bandwidth - will make it nice and fat. I'd really like to see your diagram or posts on them lows. I'm not planning on doing any freq splitting at all.

I'm a little worried about phase issues. Anyone build long chains like this with a single source? Had any issues?

[Derringer]

how many knobs?

how big of an enclosure?

[deathfaces]

this is going to be sick.

[kvb]

you might want to search Boubombilzoo. It's a mega bass fuzz with a clean blend.
It's a mixture of various ideas rolled into one pedal.
Jack Orman also provides some super simple ways of blending clean with dirt. One of these ideas is included in my schematic.

effects loop!   right there in the middle!

The Boubombilzoo has an effects loop on the fuzz side. Plus it has the ability to either turn off the fuzz or switch to a different pedal.

After finishing the pedal I figured that my advice to anyone would be to just make a buffer/splitter and a mixer - then just add effects to suit the need.

[sean k]

I would tend towards a filter of somesort before the split and can't remember what they are called... the ones that have a lowpass out, mid out and high plus a notch, state variable maybe and usually use an lm13700 or 13600. That way you define where each set of signals goes. Lows to boost with low cut, mids to soft comp and highs to fuzz, as a standard but with patching so you can change that around if needed or wanted while also being able to FX send return, then mix and EQ and out.

[bluelang]

maybe and usually use an lm13700 or 13600. That way you define where each set of signals goes.

Nice, I will look into that. Thanks!

It is an exciting time to be messin' around.. I can't believe how many functions are nicely rolled up for us into decent sounding chips these days.

[bluelang]

Using an NTE133, got the driver mocked up and biased.. It sounds really good cranked up, so good that I might build another pedal that's just an 18v supply with one of these JFETs and a couple of pots. But in the meantime, I'm trying to keep it to a reasonable 1VPP out with an input of 200mv. Really don't have a lot of headroom and REALLY don't want the op amps to clip.

And now.. bench porn!





Niiiiiice.



And then the horrible mess of 2 inputs, 2 scope probes, and 2 outputs all wanged into a single little transistor on a board.




Whole album:

http://picasaweb.google.com/bluelang/UltimateBassPedal#

[bluelang]

In case you're wondering wtf is going on there, I'm trying to listen to it both through a tiny little 2" speaker and my champ while also watching the scope. I figure I really need to get the output of the driver section correct or I'm gonna spend forever tweaking the butt-end of the pedal.